Pull rod



Nam 22, 11%49 PULL ROD Filed Aug. 18,, 1945 ikl, F i

R. $1 SPERRY Z5 (Sheets-Sheet l INVENTORU ROGER 5. SPERRY BY ATTORNEY NQV, 222 314% R. s. SPERRY fi fi FULL ROD Filed Aug. 18, 1945 3 Sheets-Sheet 2 mam\v I we I J 1 IE 10 [N VEN TOR.

ROGER S SPERRY BY 3 PULL ROD RRRRRRRRRR RY Patented Nov. 22, 1949 and Manufacturers National Bank, Waterbury, Conn., administrator of said Roger .S. Sperry,

deceased Application August 18, 1945, Serial No. 611,405

12 "Claims.

1 This invention relates to the formation of a stock or workpiece upon a forming tool in giving predetermined shape or contour to the resulting product on the tool. More particularly, the invention as herein illustrated, for example, deals with the formation of a definitely novel thread on a pull rod and in utilizing said threaded end of the rod as a forming tool upon which a workpiece is shaped to form a thread in the bore thereof, and in constructing the tool and resulting thread of the workpiece 'bore in such manner as to provide quick removal or uncoupling of the tool from the workpiece or formed product. "The .novel features of the invention will be best understood from the following description when taken together with the accompanying drawing, in which certain embodiments of the invention are disclosed, and :in which the separate parts are designated by suitable reference characters in each of the views; and in which:

Fig. 1 is a diagrammatic longitudinal sectional view through 'a pair of dies showing a pull rod made according to my invention positioned in the dies, as well as a tubular workpiece preparatory to forming the workpiece on the pull rod.

Figs. 2 to 6 inclusive are views generally similar to Fig. 1, showing successive steps in forming a workpiece upon the thread end of the pull rod, moving the pull rod with respect to the dies and introducing a mandrel in position between the dies in the reduction of a tubular workpiece; and

Fig. '7 is an enlarged sectional detailed view on the line 1-1 of Fig. 1, showing the thread con struction of the pull rod.

In the reduction of tubes, many types and kinds of devices have been employed for gripping-or otherwise engaging a pointed or otherwise formed end of a tube to facilitate drawing a tube by 'a draw bench through suitable dies. My present invention deals with the construction of a special type of tool of this kind having a. threaded end upon which a tubular workpiece may be pointed, simultaneously forming threads in the pointed end of the workpiece in providing a positive coupling of a pull rod with the tube and so con structing the threads as to provide for quick un coupling and recoupling of a pull rod therewith.

In order to clearly illustrate one adaptation and use of the invention, I have shown in Figs. 1 to 6 inclusive, successive steps oi? attaching theworkpiece to the pull rod by a pair of relatively mov able dies simultaneously in the formation of the workpiece upon a mandrel in reducing the diameter of the workpiece. These'diagrammatic illustrations of Figs. 1 to 6 inclusive aremore in detail disclosed with respect to the method in a copending application, laterto be identified by serial number and date.

In Figs. 1 to 6 inclusive, 'HI and Ill represent a pair of dies having tapered or conical worldng '2 surfaces 1 l-l l extending throughout the major portion of the length thereof from the greatest diameter, as at l-2--|2', up to but not including the smallest diameter, as at |3|3, the latter having surfaces paralleling the outer surfaces of the dies.

ln'operation of the dies, the working surfaces are moved toward and from a tubular workpiece l5, as well as the pull rod 10 and mandrel 15 in forging and cross rolling the workpiece by circumrferentially continuous inward forces applied throughout the full length of the working surfaces of the dies, with these forces diametrically opposed on the dies 1 lll'0".

Considering Fig. 1 of the drawing, .here the threaded end i! of the pull rod i4 is disposed between the dies, and theworkpiece IE is in a position preparatory to being forceably fed into the dies as said dies are given the swinging and other motions above referred to. 'In the early stages of this operation, the end of the workpiece it is first formed around the threaded end T1 of the pull rod, in the manner shown at l8 in Fig. '2 of the drawing. As the operation continues, the workpiece is further spread, by forging and cross rolling, along the thread I! to provide a greater formation around the thread, as seen at 19 in Fig. 3 of the drawing and about at this stage, the mandrel l5 or its straight forming end l5 begins to enter the dies through the tubular workpiece 16.

In Fig. 4, I have shown at 20 a greater formation -of the workpiece around the thread I? with the end [5" of the mandrel entering the die sufliciently to begin formation of the workpiece on the mandrel, as at 2|.

Returning for the moment to Fig. 3 of g the drawing, it will appear that about this stage in the operation, the pull rod l4 starts to move to the right to begin drawing the workpiece between the dies. Fig. 4 shows the workpiece move to a greater extent to the right, but with the end I! still to the left of the surfaces -l3-l3'.

In Fig. 5, the threaded end I! of the pull rod is shown beyond the limits of the surfaces 13-43, with the end l5 of the mandrel approaching said surfaces. At this particular stage, and by reason of lack of su'port within the tubular workpiece, excess metal of the workpiece is bulged into the bore thereof, as seen at 22, this bulge being disposed inwardly of and in spaced relation to the threaded end i! of the pull rod. The threads 23 are now completely formed in the workpiece around the threaded end I! of the pull rod. In Fig. 6 of the. drawing the pull rod is advanced further to the right and the reduced forming end 15" of the mandrel has been brought into its final position within and between and extending to the right slightly beyond the surfaces l3l'3" thus producing the final reduction or which the workpiece is drawn through the dies..

While certain types of dies and method of operation of the dies is illustrated, it will be apparent that any suitable dies can be employed which would perform the functions and operation upon the workpiece in shaping the workpiece around the threaded end ll of the pull rod.

In the above operation, it will be understood that the forced feed of the workpiece I6 into the dies terminates substantially when the complete pointing or forming operations of the workpiece end It has been performed on the threaded end I! of the pull rod. In utilizing the apparatus, simply for pointing the end of the tube or simply to form the threads in a tubular workpiece, the mandrel l-|5 is not essential, and after the thread has been formed therein the pull rod may be uncoupled and the workpiece removed from the dies. However, in a continuous process in reducing tubes, as disclosed diagrammatically in Figs. 1 to 6 inclusive, after the workpiece has been completely reduced and removed from the dies, then the pull rod is uncoupled with respect to the end l6 by a quick turn or rotation of the pull rod in the end [6' or vice versa, which will result in a quick uncoupling of the parts by virtue of the novel thread construction which is now defined.

In Fig. 7 of the drawing I have shown an enlarged longitudinal section, substantially on the line 1-4 of Fig. 1 of the drawing, of the threaded end I! of the pull rod l4. The threads are formed on a tapered surface and these threads are of greater width at the Wider diameter end 26 than at the narrow diameter end 21. In other words, as the threads progress from the large to the narrow end of the taper, the threads are in the form of a long spiral taper. On the other hand, the grooves 28 formed between the threads are on a greater tapered portion of the rod, so that the grooves are shallow at the wide end, as at 29, and deeper at the narrow end, as at 30, in Fig. 7 of the drawing. Further, the width of the grooves 28 at the shallow end 29 are narrower than at the deep end 30.

From a descriptive standpoint, the threaded end H may be said to comprise a spiral thread section and a spiral groove section wherein the groove section is of greater taper than the thread section, so that the groove section is deeper at the contracted end than at the wide end, and the threads are of greater depth at the contracted end than at the wider. Further, the spiral grooves are progressively tapered in the spiral from the contracted end to the wide end, whereas the spiral thread sections are progressively tapered from the wide end to the contracted end. With this type of a thread construction, one slight turn of the rod M in the workpiece or the workpiece on the rod will result in a quick release and detachment of the parts.

Working surfaces ll-I l' comprise, in the die construction shown, two tapers and for purposes of this description, will be defined as inner and outer surfaces. In Fig. 1, the references Il-l l are directed to the inner surfaces and the refer ences l2l2' are directed to the outer surfaces.

In the operation of the dies, in moving toward and from each other in the combined forging and cross rolling operations, the said inner surfaces, or at least diametrically opposed elements thereof, are parallel to each other and to the axis of the pull rod, as such diametrically opposed elements are moved inwardly to the greatest extent. In Figs. 1 to 6 inclusive, the dies are shown in what might be termed an intermediate position in their movement one with respect to the other, and in such position, the surfaces l3-I3 are parallel to each other and to the axis of the pull rod. In other words, it is the inner surfaces to which the reference numerals Il-l I have been directed, that control the final outside diameter of the product,

In uses where the workpiece is rotated relatively to the die, the threads will be formed on the pull rod so as to prevent unthreading of the rod with the workpiece in the operation of the machine. In other words, in different uses, left and right hand threads may be used on the threaded end I1, depending entirely upon the direction of rotation of the workpiece. In ordinary draw benches, a straight pull is usually provided on the pull rod and in such instances, it is obviously immaterial which of these two types of thread is used.

It will be apparent from the foregoing that the threaded end portion I! of the pull rod I4 actually comprises a forming tool or die around which a workpiece body is fashioned by the use of suitable forging or forming dies to produce a thread in the bore of the workpiece conforming to the threads of said threaded end I! of the pull rod. In the present illustration, the tool is in the form of a thread of special construction. However, in the more general consideration of the invention, it will be apparent that any type of coupling end may be provided on the tool, and accordingly, a correspondingly and fitting coupling socket can be formed in the workpiece or stock.

With the specific thread structure disclosed on the tool and formed in the resulting socket of the stock or workpiece, it will be apparent that no abutting shoulders are provided. The tapered thread of the socket may be said to fit in wedge like manner within and between the tapered thread of the rod, thus further coupling engagement is checked when these two tapers fit snugly one within the other. It will readil appear that a slight turn of one threaded part with respect to the other will quickly free the parts .and when applied to tapered wall portions, the two parts may be separated or pulled apart without the need of completely unscrewing the parts.

In describing the thread structure or section of the pull rod tip, it may be said that this threaded section has a thread whose pitch diameter progressively increases or decreases along said tip with the thread comprising a continuous taper extending spirally around the member.

In defining the structure in other terms, the thread in question may be characterized as an acme thread, wherein the flat crest diameter of the thread is on a uniform taper and the root diameter is also on a uniform taper, different from the crest diameter taper. As a result, the side wall or lead of one side of the thread is diiferent from the lead of the opposite side of the thread, these structures being clearly apparent from a consideration of Fig. 7 of the drawing. With a thread of this type and kind, it will appear that upon the first increment of the twist of the mandrel, relative to-the stock swaged thereabout, the contacting surfaces of the stock and mandrel will be completely loosened throughout their entire and various contacting surfaces.

Having fully described my invention, what I claim as new and desire to secure by Letters Platent is:

1. A pull rod for drawing stock in apparatus of the character described, a threaded portion at one end of the rod for anchorage of a workpiece thereon, the threads of the threaded portion having a flat crest and disposed on a tapered end of the rod, the groove between the thread being formed of a taper greater than the thread taper to provide deeper depth of the thread groove at the end of the rod, the thread tapering in width in the direction of the end of said rod to provide a narrow thread at said rod end, and the groove tapering in width from the end of the rod inwardly to provide a narrow groove at the inner end of said threaded portion.

2. A thread construction for rods of the class described, said thread construction comprising a continuous spiral fiat crest thread tapering longitudinally of the rod in one direction, and said rod having a spiral groove between said thread tapering in the other direction on said rod whereby .the thread is narrower in width on one end and the groove is narrower in width at the opposite end.

3. A thread construction for rods of the class described, said thread construction comprising a continuous spiral fiat crest thread tapering longitudinally of the rod in one direction, said rod having a spiral groove between said thread tapering in the other direction on said rod whereby the thread is narrower in width on one end and the groove is narrower in Width at the opposite end, said thread progressively reducing in diameter in the same direction of the taper of said thread, and the groove of the thread progressively increasing in diameter in the direction of taper of said groove.

4. A member having a quick release threaded section, said section comprising a spiral flat crest thread on said member progressively reduced in thread width in extension of the thread along said member in one direction, and said section having a thread groove intermediate said thread progressively reduced in width along said memher in the opposite direction.

5. A member having a quick release threaded section, said section comprising a spiral fiat crest thread on said member progressively reduced in thread width in extension of the thread along said member in one direction, said section having a thread groove intermediate said thread progressively reduced in width along said member in the opposite direction, and the depth of said groove being reduced as the groove extends along said member in the last named direction.

6. A quick release thread for threaded members, said member having a tapered section defined by deep and shallow tapered portions, the shallow tapered portion comprising an elongated spira1 flat crest thread, the deep tapered portion comprising a groove disposed intermediate the thread, and said groove and thread being both progressively tapered in spiral extension thereof longitudinally of said member and to dispose the narrow end of the thread in a direction opposed to the narrow end of the groove on said member.

7. A quick thread coupling between two parts, comprising an externally threaded part and an internally threaded part, the threads of said parts snugly interfitting when the parts are coupled itO- gether, the thread of the externally threaded part comprises a spiral flat crest thread progressively reduced in width in one direction alOng said part, and said externally threaded part having a thread groove progressively tapered in width in the opposite direction on said part.

8. A quick thread coupling between two parts, comprising an externally threaded part and an internally threaded part, the threads of said parts snugly interfitting when the parts are coupled together, the thread of the externally threaded part comprises a spiral flat crest thread progressively reduced in width in one direction along said part, said externally threaded part having a thread groove progressively tapered in width in the opposite direction on said part, and the depth of the thread groove being progressively reduced in said last named direction.

9. A quick detachable thread structure for devices of the character described, said device having a longitudinal threaded section, and the thread and groove defining the threaded section comprising a progressively tapering fi-at crest thread and groove with the thread tapered in 'a direction opposed to the taper of the groove.

10. A quick detachable thread structure :for devices of the character described, said device having a longitudinal threaded section, the thread and groove defining the threaded section comprising .a progressively tapering flat crest thread and groove with the thread tapered in a direction opposed to the ,taper of the groove, and the pitch diameter of the thread forming a progressively increasing spiral in one direction along said threaded section.

11. A thread construction for rods of the class described, said thread having a flat crest surface formed on a uniformly tapered portion of said rod, the crest diameter of said thread being also uniformly tapered but of a less degree to the axis than said rod taper, and the side walls of said thread being tapered relative to rod taper with the helical lead of one side wall differing from the helical lead of the opposite side wall such that the thread width progressively decreases in width from the terminal tapered end of the rod toward the full diameter of the rod.

12. A thread construction for rods of the class described, said thread being arranged on one end portion of said rod and having a crest diameter tapering toward said end of the rod and a root diameter also tapering toward said end of the rod but on a greater degree than said crest diameter, and the pitch lead of one side of the thread being difierent from pitch lead on the opposite side of the thread, whereby a quick release can be obmined by any member swaged about the threaded section of said rod throughout its entire contacting surface upon a twist of said member relative to said rod.

ROGER S. SPERRY.

REFERENCES 'CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 105,818 Lord July 26, 1870 359,755 Wicks Mar. 22, 1887 561,327 Larson June 2, 1896 1,927,656 Eaton et al Sept. 19, 1933 2,267,923 Johnson Dec. 30, 1941 2,353,030 Green July 4, 1944 

